//-----------------------------------------------------------------------------
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//-----------------------------------------------------------------------------
// Project    : Spartan-6 Integrated Block for PCI Express
// File       : PIO_TO_CTRL.v
// Description: Turn-off Control Unit.
//
//-----------------------------------------------------------------------------

`timescale 1ns/1ns

module PIO_TO_CTRL (
  input      clk,
  input      rst_n,

  input      req_compl_i,
  input      compl_done_i,

  input      cfg_to_turnoff,
  output reg cfg_turnoff_ok
  );

  localparam TCQ = 1;
  reg        trn_pending;

  //
  //  Check if completion is pending
  //
  always @(posedge clk) begin
    if (!rst_n) begin
      trn_pending   <= #TCQ 0;
    end else begin
      if (!trn_pending && req_compl_i)
        trn_pending <= #TCQ 1'b1;
      else if (compl_done_i)
        trn_pending <= #TCQ 1'b0;
    end
  end

  //
  //  Turn-off OK if requested and no transaction is pending
  //
  always @(posedge clk) begin
    if (!rst_n) begin
      cfg_turnoff_ok   <= #TCQ 1'b0;
    end else begin
      if (cfg_to_turnoff  && !trn_pending)
        cfg_turnoff_ok <= #TCQ 1'b1;
      else
        cfg_turnoff_ok <= #TCQ 1'b0;
    end
  end

endmodule // PIO_TO_CTRL

